Electrically-powered unmanned marine vehicle and method of making same

A method of manufacturing an electrically-operable unmanned fully-submersible underwater vehicle, comprising:

• providing at least a hull of the fully-submersible underwater vehicle;
• manufacturing a gearless water-cooled submersible brushless electric thruster, including:
• providing a stator assembly having electrical windings, and applying a protective barrier directly to the electrical windings,
• wherein the applying the protective barrier includes applying a plastic coating in liquefied form directly to the electrical windings such that upon solidification of the plastic coating the plastic coating covers the electrical windings;
• and
• wherein the stator assembly further includes a stationary base extending radially relative to a longitudinal axis of the thruster, and a stationary support tube projecting from the base in which the support tube extends in a direction of the longitudinal axis, and in which the electrical windings are supported by the stationary support tube and the stationary base, wherein the support tube includes an opening at an axial end thereof, and includes an internal passage extending from the opening along the longitudinal axis;
• providing a rotor assembly including a rotatable hub, a rotatable shaft, an internal cavity, a plurality of magnets, and at least one propeller blade;
• wherein:
• the rotatable shaft extends at least partially within the internal cavity along the longitudinal axis of the thruster,
• the rotatable hub includes a cylindrical wall extending circumferentially about the rotatable shaft, and includes an end wall connected to the cylindrical wall in which the end wall extends transverse to the longitudinal axis and in which the rotatable shaft is fixed to the end wall for co-rotation therewith,
• the plurality of magnets are operatively mounted to the cylindrical wall for co-rotation therewith, wherein the plurality of magnets are arranged radially outwardly of at least a portion of the internal cavity about the rotatable shaft;
• the end wall and the cylindrical wall enclose respective portions of the internal cavity, and wherein an opening to the internal cavity is formed at an end of the cylindrical wall opposite the end wall thereby allowing flow of water to the internal cavity when the thruster is submerged;
• the at least one propeller blade is operatively coupled to the rotatable hub for co-rotation therewith, the at least one propeller blade being configured to generate thrust and propel the underwater vehicle during operation of the thruster when under water;
• assembling the stator assembly and the rotor assembly together, such that:
• the rotatable shaft of the rotor assembly is inserted through the opening and into the internal passage of the support tube of the stator assembly;
• the electrical windings are arranged within the internal cavity of the rotor assembly, the electrical windings being arranged radially inwardly of the plurality of magnets and radially outwardly about the rotatable shaft;
• a flow passage is provided between the rotor and stator assemblies, the flow passage being configured to allow the internal cavity to be flooded with water when the thruster is submerged, and the protective barrier covering the windings is configured to prevent the flooded water from contacting the windings, and
• the plurality of magnets are configured to rotate about the electrical windings and protective barrier when driven by electromagnetic forces provided by the electrical windings during operation of the thruster in water thereby rotating the propeller and generating sufficient thrust to propel the fully-submersible underwater vehicle when under water;
• coupling the stator assembly to an annular nozzle such that stator assembly is disposed radially inwardly of the annular nozzle, wherein the annular nozzle has an inlet opening and outlet opening configured to allow water to flow therethrough;
• and
• mounting the gearless water-cooled submersible brushless electrical thruster to the hull of the fully-submersible underwater vehicle such that the thrust generated by the thruster translates to movement of the fully-submersible underwater vehicle when in use under water.